[Cloning of promoter of banana fruit-specific ACC synthase gene and primary study on its function]

Based on our cDNA sequence of ACC synthase gene expressed specifically in banana fruit, we cloned the 5'-flanking proximal region of 1197 bp and distal region of 1556 bp via walking on unknown region of genomic DNA by an improved adaptor ligation PCR, and created a 2591 bp fragment containing a promoter region of 2505 bp and a transcriptional region of 86 bp. The entire 2.5 kb promoter and 5 different 5' deletion variants were fused to the GUS (beta-glucuronidase) cDNA sequence and introduced into leaf, root and fruit cells of banana plant via particle bombardment separately. The results of transient gene expression assay indicated that the obtained promoter region could direct fruit-specific gene expression. The regulatory region for fruit-specificity was possibly located in the region from -1111 to +1 and a positive regulatory region may locate between nucleotide -1111 to -608.